size 11.4 1.64 ! 4*x2+2*(x4+d1+d) y1+y+2*d include "feyn.gle" x = 0.8 x1 = 1.6 x2 = 2 x3 = 0.72 x4 = 1.2 y = 0.56 y1 = 0.88 d = 0.1 d1 = 0.4 r = 0.05 doublea = 0.05 a = 1.75*doublea sub quad x y amove x-a y-a begin path fill black rline 2*a 0 rline 0 2*a rline -2*a 0 rline 0 -2*a end path amove x y end sub begin translate x2+d d amove -x2 0 @double x2 0 amove -x1 0 circle r fill black photonn = -1 @photon -x y1 circle r fill black set lwidth 0.06 @fermion2 0 y1+y x y1 set lwidth 0.03 circle r fill black set lwidth 0.06 @fermion2 0 y1-y -x y1 set lwidth 0.03 amove x1 0 circle r fill black photona = -photona photonn = -1 @photon x y1 photona = -photona @quad 0 0 end translate begin translate 3*x2+d1+d d amove -x2 0 @double x2 0 @quad -x1 0 amove -x1 0 photonn = -1 @photon -x y1 circle r fill black set lwidth 0.06 @fermion2 0 y1+y x y1 set lwidth 0.03 circle r fill black set lwidth 0.06 @fermion2 0 y1-y -x y1 set lwidth 0.03 amove x1 0 circle r fill black photona = -photona photonn = -1 @photon x y1 photona = -photona end translate begin translate 4*x2+x4+2*d1+d d amove -x4 0 @double x4 0 @quad 0 0 amove 0 0 @photon2 -x3 0.5*y1 -x y1 circle r fill black set lwidth 0.06 @fermion2 0 y1+y x y1 set lwidth 0.03 circle r fill black set lwidth 0.06 @fermion2 0 y1-y -x y1 set lwidth 0.03 amove 0 0 photona = -photona @photon2 x3 0.5*y1 x y1 photona = -photona end translate